I've always thought that lichens were only found on hundreds- or thousands-of-years-old rock exposures. But, we have a deck table with a metal mesh top. It was

I've always thought that lichens were only found on hundreds- or thousands-of-years-old rock exposures. But, we have a deck table with a metal mesh top. It was last painted about 15 years ago, and is outdoors year round. A few years back I was amazed to see that flecks of lichen had colonized the table top. I guess they grow faster than I thought.